1. Field of Invention
The invention relates to a wind energy forecasting method with extreme wind speed prediction function.
2. Related Art
Due to the problems of energy deficiency, global warming and serious climatic changes, using renewable resources for power generation has become the proper solution to the problems. Renewable resources include wind energy, solar energy, biomass energy, geothermal energy, etc. Because of lower cost and high economic effect, wind power generation has been developed rapidly in the past few years.
In general, a wind power generator includes an impeller, a gearbox, a power generator, a shifting apparatus and a controlling system. The impeller has a set of blades well designed by fluid dynamics and installed to the axle. When wind passes through the blades, the impeller can be forced to rotate, resulting in kinetic power that is transmitted through the transmission system and gearbox to the power generator to generate electricity. The controlling system can control the shifting apparatus according to the wind direction signal from the wind direction sensor, so that the wind power generator can automatically maintain the proper orientation against the wind to optimize the power generation efficiency.
Strong and predictable output of wind energy is the primary requisite to develop wind power generation. However, the wind as the source of the wind power generation is naturally generated and unstable, so a well developed wind energy prediction system is needed to improve the usage of wind power generation and keep the security of power supply system.
In practical operations, the short-term wind energy forecasting can predict and follow the output variations of wind power generation at the wind farms within 48 hours in the future, which can increase the electricity output of the wind farm. For purpose of maintenance, the prediction with a longer scale is used to determine the timing of maintenance so that the cost of power generation business can be lowered down. Accordingly to the estimation of a famous wind energy consultant company, the short-term wind energy prediction can bring the benefit of 7 Euros per million watt hour (MWH) by considering a single wind farm in Spain. Of course, the combination prediction of plural wind farms can be more precisely and get more benefit. Therefore, many countries are devoted to the wind energy prediction system and technology to enhance the business efficiency of wind farms.
Taiwan is an island nation located in the western Pacific Ocean. Taiwan suffers many typhoons every year, and besides, the undulation of Taiwan's landform varies a lot, with more than 100 mountains higher than 3000 meters. Therefore, the track and strength of the typhoon always varies capriciously when typhoons pass through Taiwan. Typhoons had destroyed a lot of wind turbines in Taiwan. Different kinds of wind turbines designed to against different levels of strength of the wind speed, if the extreme wind speed exceeds the upper limitation of the wind turbine, the security problem of the wind turbine will occur.
Therefore, it is a very important subject to provide a wind energy forecasting method with extreme wind speed prediction function that can provide wind energy prediction with considering the specific weather (e.g. typhoons, hurricanes, etc.) so as to improve the efficiency of wind power generation, and can predict the extreme wind speed of the typhoon when the typhoon comes so as to avoid the security problem of the wind turbines.